What is "Kol ha'Erev"?
Rashi: Sumchavasa (Targum Yonasan). This is what Pharaoh relied on for help, his guarantors.
Radak: Sumchavasa (Targum Yonasan). This is an expression of a mixture. Malbim - it was a mixture of nations, therefore it does not say Malchei ha'Erev 1 .
Our texts of Yonason say Malchei Sumchavasa! And verse 24 says Malchei ha'Erev! (PF)
Are "Kol Malchei Eretz Pelishtim" the ones listed after this?
Radak: No, they are the others, who are not listed here. Also in Shmuel I, 6:18, after it lists the cities that gave Techorei ha'Zahav, it says also "me'Ir Mivtzar v'Af Kofer ha'Perazi."
What is "She'eris Ashdod"?
Radak: When Nebuchadnetzar conquered it, he found it partially destroyed via Melech Egypt or someone else.
Why is Gas not listed among the Pelishti cities?
Radak: It belonged to Yisrael after David took it from the Pelishtim, like it says in Divrei ha'Yamim (I, 18:1) "David... va'Yikach Es Gas u'Vnoseha mi'Yad Pelishtim." This is Meseg ha'Amah mentioned in Shmuel II, 8:1.